The use of thin walled plastic shells for products have included a cast shell of thermoplastic material with a decorative feature formed therein. One example is set forth in U.S. Pat. No. 4,610,620, which discloses apparatus for molding plural colored plastic hollow shells by a process in which a decorative pinstripe is formed as an integrally bonded joint between first and second segments of the shell. The joint between the shell components is used to replace a mechanical connection therebetween and to provide a pinstripe decorative feature in the shell component. However, the decorative pinstripe is formed only along the joint line of the joined parts and is not formed in situ in a base layer.
U.S. Pat. No. 4,562,025 discloses a mold method and apparatus for multicolored plastic shells which have first and second colored segments on the cast shell portions of the finished product. However, there are no decorative features formed in situ on the cast shell components of the trim part.
U.S. Pat. No. 4,562,032 discloses a method for forming grain coverings on reaction injection molded articles. Such grained shells are formed, in some cases, to have an integrally formed stitching feature around the perimeter thereof to provide an appearance of stitched materials.
U.K. Patent Application GB 2,174,953A discloses a rotational mold process wherein indicia is first cast and fused in a recessed mold. The recessed mold is then connected to a rotational mold to deposit a backing layer of thermoplastic material. There is no suggestion of an intermediate step to stabilize and protect partially fused material on a mold for subsequent handling.
While the above patents disclose shells cast from thermoplastic material which include decorative color and trim features, they do not disclose a method for providing decorative features such as colored lettering or colored stitching in situ on an eye discernible surface of a finished article wherein the decorative feature is partially fused, protected and stabilized prior to rotational molding a base layer thereon.